package com.feidian.helper.net;
import java.io.File;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import android.content.Context;
import android.util.Log;

import com.feidian.helper.service.FileService;



public class FileDownloader {

    private static final String TAG = "FileDownloader";

    private Context context;

    private FileService fileService;    
    /* 已下载文件长度 */
    private int downloadSize = 0;
    /* 原始文件长度 */

    private int fileSize = 0;
    /* 线程数 */

    private DownloadThread[] threads;
    /* 本地保存文件 */

    private File saveFile;
    /* 缓存各线程下载的长度*/

    private Map<Integer, Integer> data = new ConcurrentHashMap<Integer, Integer>();

    /* 每条线程下载的长度 */

    private int block;

    /* 下载路径  */

    private String downloadUrl;

    /**

     * 获取线程数

     */

    public int getThreadSize() {

        return threads.length;

    }

    

    /**

     * 获取文件大小

     * @return

     */

    public int getFileSize() {

        return fileSize;

    }

    /**

     * 累计已下载大小

     * @param size

     */

    protected synchronized void append(int size) {

        downloadSize += size;

    }

    /**

     * 更新指定线程最后下载的位置

     * @param threadId 线程id

     * @param pos 最后下载的位置

     */

    protected synchronized void update(int threadId, int pos) {

        this.data.put(threadId, pos);

        this.fileService.update(this.downloadUrl, this.data);

    }

    /**

     * 构建文件下载器

     * @param downloadUrl 下载路径

     * @param fileSaveDir 文件保存目录

     * @param threadNum 下载线程数

     */

    public FileDownloader(Context context, String downloadUrl, File fileSaveDir, int threadNum) {

        try {

            this.context = context;

            this.downloadUrl = downloadUrl;

            fileService = new FileService(this.context);

            URL url = new URL(this.downloadUrl);

            if(!fileSaveDir.exists()) fileSaveDir.mkdirs();

            this.threads = new DownloadThread[threadNum];                    

            

            HttpURLConnection conn = (HttpURLConnection) url.openConnection();

            conn.setConnectTimeout(5*1000);

            conn.setRequestMethod("GET");

            conn.setRequestProperty("Accept", "image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*");

            conn.setRequestProperty("Accept-Language", "zh-CN");

            conn.setRequestProperty("Referer", downloadUrl); 

            conn.setRequestProperty("Charset", "UTF-8");

            conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.2; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)");

            conn.setRequestProperty("Connection", "Keep-Alive");

            conn.connect();

            printResponseHeader(conn);

            

            if (conn.getResponseCode()==200) {

                this.fileSize = conn.getContentLength();//根据响应获取文件大小

                if (this.fileSize <= 0) throw new RuntimeException("Unkown file size ");

                        

                String filename = getFileName(conn);//获取文件名称

                this.saveFile = new File(fileSaveDir, filename);//构建保存文件

                Map<Integer, Integer> logdata = fileService.getData(downloadUrl);//获取下载记录

                

                if(logdata.size()>0){//如果存在下载记录

                    for(Map.Entry<Integer, Integer> entry : logdata.entrySet())

                        data.put(entry.getKey(), entry.getValue());//把各条线程已经下载的数据长度放入data中

                }

                

                if(this.data.size()==this.threads.length){//下面计算所有线程已经下载的数据长度

                    for (int i = 0; i < this.threads.length; i++) {

                        this.downloadSize += this.data.get(i+1);

                    }

                    

                    print("已经下载的长度"+ this.downloadSize);

                }

                

                //计算每条线程下载的数据长度

                this.block = (this.fileSize % this.threads.length)==0? this.fileSize / this.threads.length : this.fileSize / this.threads.length + 1;

            }else{

                throw new RuntimeException("server no response ");

            }

        } catch (Exception e) {

            print(e.toString());

            throw new RuntimeException("don't connection this url");

        }

    }

    

    /**

     * 获取文件名

     * @param conn

     * @return

     */

    private String getFileName(HttpURLConnection conn) {

        String filename = this.downloadUrl.substring(this.downloadUrl.lastIndexOf('/') + 1);

        

        if(filename==null || "".equals(filename.trim())){//如果获取不到文件名称

            for (int i = 0;; i++) {

                String mine = conn.getHeaderField(i);

                

                if (mine == null) break;

                

                if("content-disposition".equals(conn.getHeaderFieldKey(i).toLowerCase())){

                    Matcher m = Pattern.compile(".*filename=(.*)").matcher(mine.toLowerCase());

                    if(m.find()) return m.group(1);

                }

            }

            

            filename = UUID.randomUUID()+ ".tmp";//默认取一个文件名

        }

        

        return filename;

    }

    

    /**

     *  开始下载文件

     * @param listener 监听下载数量的变化,如果不需要了解实时下载的数量,可以设置为null

     * @return 已下载文件大小

     * @throws Exception

     */

    public int download(DownloadProgressListener listener) throws Exception{

        try {

            RandomAccessFile randOut = new RandomAccessFile(this.saveFile, "rw");

            if(this.fileSize>0) randOut.setLength(this.fileSize);

            randOut.close();

            URL url = new URL(this.downloadUrl);

            

            if(this.data.size() != this.threads.length){

                this.data.clear();

                

                for (int i = 0; i < this.threads.length; i++) {

                    this.data.put(i+1, 0);//初始化每条线程已经下载的数据长度为0

                }

            }

            

            for (int i = 0; i < this.threads.length; i++) {//开启线程进行下载

                int downLength = this.data.get(i+1);

                

                if(downLength < this.block && this.downloadSize<this.fileSize){//判断线程是否已经完成下载,否则继续下载    

                    this.threads[i] = new DownloadThread(this, url, this.saveFile, this.block, this.data.get(i+1), i+1);

                    this.threads[i].setPriority(7);

                    this.threads[i].start();

                }else{

                    this.threads[i] = null;

                }

            }

            

            this.fileService.save(this.downloadUrl, this.data);

            boolean notFinish = true;//下载未完成

            

            while (notFinish) {// 循环判断所有线程是否完成下载

                Thread.sleep(900);

                notFinish = false;//假定全部线程下载完成

                

                for (int i = 0; i < this.threads.length; i++){

                    if (this.threads[i] != null && !this.threads[i].isFinish()) {//如果发现线程未完成下载

                        notFinish = true;//设置标志为下载没有完成

                        

                        if(this.threads[i].getDownLength() == -1){//如果下载失败,再重新下载

                            this.threads[i] = new DownloadThread(this, url, this.saveFile, this.block, this.data.get(i+1), i+1);

                            this.threads[i].setPriority(7);

                            this.threads[i].start();

                        }

                    }

                }    

                

                if(listener!=null) listener.onDownloadSize(this.downloadSize);//通知目前已经下载完成的数据长度

            }

            

            fileService.delete(this.downloadUrl);

        } catch (Exception e) {

            print(e.toString());

            throw new Exception("file download fail");

        }

        return this.downloadSize;

    }

    

    /**

     * 获取Http响应头字段

     * @param http

     * @return

     */

    public static Map<String, String> getHttpResponseHeader(HttpURLConnection http) {

        Map<String, String> header = new LinkedHashMap<String, String>();

        

        for (int i = 0;; i++) {

            String mine = http.getHeaderField(i);

            if (mine == null) break;

            header.put(http.getHeaderFieldKey(i), mine);

        }

        

        return header;

    }

    

    /**

     * 打印Http头字段

     * @param http

     */

    public static void printResponseHeader(HttpURLConnection http){

        Map<String, String> header = getHttpResponseHeader(http);

        

        for(Map.Entry<String, String> entry : header.entrySet()){

            String key = entry.getKey()!=null ? entry.getKey()+ ":" : "";

            print(key+ entry.getValue());

        }

    }



    private static void print(String msg){

        Log.i(TAG, msg);

    }

}